title: The relationship between serum amyloid A and apolipoprotein A-I in high-density lipoprotein isolated from patients with coronary heart disease.
abstract: BACKGROUND
  Alteration in the protein composition of high-density lipoprotein (HDL) has been proposed as a mechanism for the development of coronary heart disease (CHD). In HDL, an increase in serum amyloid A protein (SAA) accompanying the decrease in apolipoprotein A-I (apoA-I) has been found during the acute inflammation period. However, whether this phenomenon persists in CHD patients, a disease related to inflammation, is unknown. The purpose of the present study was to explore the relationship between SAA and apoA-I in HDL isolated from CHD patients.
  
  
  METHODS
  Overall, 98 patients with confirmed stable CHD and 90 control subjects matched for age and gender were enrolled in this case-control study. Potassium bromide (KBr) density gradient ultracentrifugation was used to isolate HDL from plasma. The levels of SAA and apoA-I in the HDL samples were detected by enzyme-linked immunosorbent assay kits. Pearson's correlation and general linear models were used in the analysis.
  
  
  RESULTS
  Compared with controls, patients with CHD had a significant decrease in the amount of apoA-I ((14.21 ± 8.44) µg/ml vs. (10.95 ± 5.95) µg/ml, P = 0.003) in HDL and a significant increase in the amount of log SAA (1.21 ± 0.46 vs. 1.51 ± 0.55, P < 0.00001). Differences were independent of age, body mass index (BMI), HDL cholesterol (HDL-C), and other factors. An independently and statistically significant positive correlation between log SAA and apoA-I in HDL was observed only in the CHD group (β = 2.0, P = 0.026). In the general linear model, changes in log(SAA), age, age2, gender, BMI and HDL-C could explain a statistically significant 43% of the variance in apoA-I.
  
  
  CONCLUSIONS
  This study provides direct evidence for the first time that there was an independent positive correlation between log SAA and apoA-I in the HDL of CHD patients, indicating the alteration of protein composition in HDL. However, the question of whether this alteration in HDL is associated with impairment of HDL functions requires further research.
authors.affiliation: Key Laboratory of Clinical Trial Research in Cardiovascular Drugs, Ministry of Health, State Key Laboratory of Cardiovascular Diseases, Fuwai Hospital, National Center for Cardiovascular Diseases, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100037, China.
authors.forename: Dong-xue
authors.initials: DX
authors.lastname: Wang
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.forename: Li-rong
authors.initials: LR
authors.lastname: Yan
authors.forename: Ye-ping
authors.initials: YP
authors.lastname: Zhang
authors.forename: Xiao-yuan
authors.initials: XY
authors.lastname: Guan
authors.forename: Zhi-min
authors.initials: ZM
authors.lastname: Xu
authors.forename: You-hong
authors.initials: YH
authors.lastname: Jia
authors.forename: Yi-shi
authors.initials: YS
authors.lastname: Li
mesh_terms: D000328:Adult; D000368:Aged; D016632:Apolipoprotein A-I / Q000032:analysis*; D003327:Coronary Disease / Q000097:blood* / Q000209:etiology; D005260:Female; D006801:Humans; D008075:Lipoproteins, HDL / Q000032:analysis* / Q000097:blood; D008297:Male; D008875:Middle Aged; D000685:Serum Amyloid A Protein / Q000032:analysis*
chemical_list: D016632:Apolipoprotein A-I; D008075:Lipoproteins, HDL; D000685:Serum Amyloid A Protein